The aim of this paper is to study at firm level the role of public banking as an attenuator of market failures and as development instrument. We analyze the differential characteristics of small and medium enterprises in relation to their funding through private and public banks, comparing Argentina and Brazil. We use the World Bank Enterprise Surveys database. The results are in line with expectations, showing that smaller companies are more likely to have loans in public banks. As differential results between countries, in Argentina the variables that show a negative effect are belonging to the industrial sector, and having a higher percentage of sales devoted to the domestic market. In contrast, in Brazil it adversely affects that the company director is a woman.